Marker assisted selection for introgression of bacterial blight (BB) resistance genes in rice (Oryza sativa L.)
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Date
2013
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CCSHAU
Abstract
The present investigation was undertaken to introgress the major BB resistance genes (Xa21, xa13 and xa5) into BB susceptible rice variety CSR-30, from BB resistant donor varieties Pusa Basmati -1460 (having two BB resistance genes Xa21 and xa13) and IRBB-60 (having three BB resistance genes Xa21, xa13 and xa5) through marker assisted selection.
Crosses were made between CSR-30 x Pusa Basmati -1460 and CSR-30 x IRBB-60. Foreground selection was carried out in F1 plants of both the crosses using specific STS markers pTA248, RG136 and RG556 linked to Xa21, xa13 and xa5, genes respectively. In cross CSR-30 x Pusa Basmati -1460, four F1 seeds were harvested. Foreground selection was carried out in which two plants were found to have both the BB resistance genes Xa21and xa13. These F1 plants were grown in the net house and selfed to get F2 seeds. In cross CSR-30 x IRBB-60, 6 F1 seeds were harvested. Foreground selection was carried out and three plants were found to have three resistance genes Xa21, xa13 and xa- 5. Backcrosses of these positive F1 plants were made with CSR-30 and the BC1F1 seeds of this cross harvested. These BC1F1 seeds were selfed to produce BC1F2 seeds. In foreground selection, 10/250 BC1F2 plants were found to have all the three resistance genes Xa21, xa13 and xa-5. For background selection, 300 SSR primers were used to identify the polymorphism between parental genotypes Pusa Basmati-1460 and CSR-30 and between IRBB-60 and CSR-30, out of which 72 and 104 SSR markers produced polymorphic alleles between the parents Pusa Basmati-1460 and CSR-30 and parents IRBB- 60 and CSR-30, respectively. Cluster tree analysis revealed that the three gene pyramided BC1F2 rice genotypes and the recipient parent CSR-30 fell in one group with two major sub-groups and the donor parent IRBB-60 remained as a separate group. The percentage recovery of recurrent parent genome in the three-gene pyramided BC1F2 genotypes ranged from 44.2% to 78.9% using GGT software. The pyramided lines exhibited very high level of resistance to bacterial blight disease when artificially inoculated with Xanthomonas oryzae strain isolated from the BB infected fields of RRS, Kaul, CCSHAU, Hisar. The agro-morphological traits of the three-gene pyramided BC1F2 genotypes were found to be either superior or on par with the recurrent parent CSR-30. Genotype G-3 showed the best agronomic features with maximum recovery of recurrent parent genome (RPG) 78.9% followed by G-169 with RPG 76.2% followed by line G-7 with RPG 72.5%. The plants having maximum recurrent parent genome were backcrossed with the recurrent parent CSR-30 and BC2F2 seeds were harvested. It is suggested that positive F2 seeds of cross CSR-30 x Pusa Basmati -1460 should be backcrossed with CSR-30 for further work. However, in cross CSR-30 x IRBB-60, BC2F2 genotypes should be further Evaluated for agronomic traits. This work demonstrates the successful application of MAS for targeted introgression of multiple resistance genes into premium quality rice variety CSR-30.
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Keywords
Genes, Rice, Planting, Genotypes, Diseases, DNA, Selection, Genomes, Genetics, Bacteria